Costs

This entire process of designing an engineered septic system consists of
several very distinct elements. Although each project is different, there are some
similarities between projects. Listed below are some typical engineering costs for the
development of a residential onsite wastewater disposal system.

During this phase, the Engineer walks the site seeking topical information on soil
types, access of heavy equipment (essential for the Site Assessment), as well as
setback and siting constraints (e.g., creeks, excessive slopes, cut banks, etc.).

Excavations are made by a backhoe in the soil strata so that soil profiles may
be examined closely. The soil strata is examined to determine the feasibility of siting an
on-site system, the optimal area for a leachfield, the type of disposal system, and the
depths at which to perk. Typically, the holes are excavated by a backhoe, but in some
situations (e.g., repairs, small sites, and sites with difficult access), auguring by hand is
more appropriate. Often, with the Client's permission, a member of the local health
department staff is invited to participate in this process.

The State Regional Water Quality Control Board requires that there be a
minimum of three feet separation between groundwater and impermeable soils.
Consequently, in some counties it is required that the seasonal groundwater, which
comes close to the surface, be monitored during the winter. Typically, this is required on
level sites, sites with slower permeable soils, and in areas of very high permeability. This
is often monitored after some specific precipitation condition (e.g., after 50% of the
seasonal rainfall has occurred).

Percolation tests are either steady head or falling head analyses. These tests
are typically conducted in those substrata deemed permeable during the site
assessment process and situated in compliance with various regulatory standards
(e.g., >2 to 3 feet above groundwater and impermeable stratum).

There are four components to percolation testing: construction of the
percolation holes; pre-soaking the holes the day before the testing; the actual
percolation test; analysis of the results.

There are a number of treatment and leachfield designs - including a "standard
system" - which are available. Typically based on site conditions, these designs are
described in the EEA publication titled Summary/Onsite Wastewater Disposal
Systems. Included in this phase are both the preparation of a topographic map for the
disposal site, and the preparation of the Plans and Specifications.

1 The amount of the fee is dependent on the County.

2 The cost for this engineering is a function of the size of the parcel, the projected size of the system,
the difficulty of the site, the use of heavy equipment, and the amount of time necessary to complete the task.

3 Currently, this is only required in Marin and Sonoma Counties.

4 The higher fee is for Counties where multiple monitoring is required.

5 Engineering cost per field tested.

Construction costs and inspections, as well as liaison with the client and
regulatory staff may vary greatly between sites, Consequently, they are not
represented here.